Returns the recruitment time for each subject
get.recruitment.time(
x,
to.numeric = TRUE,
wave.fallback = FALSE,
check.type = TRUE
)
the rds.data.frame
if true, time will be converted into a numeric variable.
if true, subjects' recruitment times are ordered by wave and then by data.frame index if no recruitment time variable is available.
if true, x is required to be of type rds.data.frame